1. Field of the Invention
The present invention related to a halogen-free polymer resin composition and a polymer resin material made from the composition, particularly a cable for ships or drillships. The polymer resin material made from the composition according to the present invention maintains its flexibility even at a low temperature of −40° C. It has not only flame retardancy that satisfies the requirements for use in a cable for general ships, but also oil resistance that satisfies the requirements for use in marine structures such as oil well drilling ships, oil well drilling structures or drillships.
2. Description of Related Art
In recent years, the use of a halogen such as bromine or chlorine has been partially limited in many countries. This is because halogen-containing compounds have been reported to generate environmental hormones, which result in carcinogenesis, skin diseases, a decrease in immunity, a delivery of deformed babies and a toxicity to the human body. In addition, halogens can cause chemical reactions by water and heat, resulting in highly toxic products. Particularly, when a fire breaks out in, for example, ships provided with halogen-containing cables, the risk of human casualties will further increase due to harmful gases. Therefore, the NGO Greenpeace and the like are offering environment-friendly guides that recommend no use of halogen-containing products, and many companies have also developed halogen-free products.
Moreover, cables for use in marine structures such as oil well drilling ships, oil well drilling structures or drillships are required to have more excellent oil resistances compared to cables for use in general ships, and need to maintain their flexibility even at low temperatures such as −40° C. In connection with this, it is very difficult for a cable sheath material having flexibility at a low temperature of −40° C. to satisfy both the oil resistance requirement of IEC 60092-359 and the oil resistance requirement of the NEK 606. This is because IRM 903 oil used in NEK 606 has higher aromatic hydrocarbon content than IRM 902 oil used in IEC 60092-359, and ethylene vinyl acetate contained in cables has poor resistance to the aromatic hydrocarbons. For this reason, stronger oil resistances are required under the conditions using IRM 903 oil. Furthermore, cables for use in oil well drilling ships or drillships are used in more severe environment than cables for general ships, and this it should satisfy more strict requirements.